This invention concerns the forming of blocks of frozen foodstuff into shaped portions which correspond in appearance to the typical presentation of a cut or fillet of the original foodstuff.
Where filleted fish is frozen en masse in a plate freezer on a trawler and delivered as a block of frozen fish in ice to a food processor, it is known to divide up the block into small briquettes of frozen fish and to then form the briquettes into a shape corresponding to a fish fillet. This saves defrosting the block, separating the individual fillets and re-freezing them, which is not only time and energy consuming, but can spoil the foodstuff.
Blocks of frozen chicken fillets can be formed and handled in the same way.
Blocks of frozen fillets en masse as described will be referred to as frozen consolidated foodstuff.
It will be appreciated that whereas individual fillets of fish or chicken can vary in size, by carving up a solid mass of filleted fish or chicken and forming briquettes which are virtually 100% xe2x80x9cmeatxe2x80x9d, and then re-forming the briquette into a fillet shape, will produce uniform size and volume pieces of foodstuff, which is ideal for packaging and retailing.
The essential difference between a formed briquette and a frozen individual fillet, is that the briquette may contain xe2x80x9cmeatxe2x80x9d from two or more fillets from the original block of filleted material, but the separate portions of meat tend to become bonded by the forming process. In practice, it has been found that consumers hardly notice any difference between a xe2x80x9creconstituted filletxe2x80x9d and an original fillet. This is particularly so where the filleted material is coated with a rich sauce or is covered by breadcrumbs or other coating.
It has been known for many years that the texture and bite to the foodstuff after forming from frozen briquettes can be affected if excessive pressure is applied to the material to form the briquette into the desired end product shape.
With this in mind it is an object of the present invention to provide an improved method of forming briquettes of frozen consolidated foodstuff material as aforesaid to produce shaped portions corresponding to fillets or cuts or meat or fish which would normally be obtained by cutting or filleting a fresh fish or fresh chicken joint.
According to the present invention a large block of frozen consolidated foodstuff is cut into a plurality of small briquettes the volume of each of which is carefully controlled so as to bear a particular relation to the volume of a cavity in tooling which is formed when two parts of the tooling are brought together under pressure, and into which the briquette is to be placed to form it into a final shape.
The tooling may be two part tooling with part of the internal cavity formed by a cut-away region in both of two opposed generally flat faces of the two tooling parts.
Alternatively the cavity may be formed by a cut-away region in the flat face of one tooling part as this is moved into contact with a generally flat surface of the other tooling part making up the two part tooling.
The cutting of the block is preferably undertaken using a guillotine but where the initial block is too large to be cut by a guillotine, a bandsaw or other cutting device may be employed so as to reduce the initial block size into sections which subsequently can be cut using a guillotine.
This is to advantage since guillotining results in very little waste material in the form of xe2x80x9csawdustxe2x80x9d which, although it can be recovered and reconstituted into a paste for filling cavities in forming tooling, the resulting product after cooking has the texture and bite which is very different from that of the actual fish or chicken.
By selecting the position of the cuts, so the size of briquettes formed from the large mass of frozen foodstuff can be controlled by reference to their volume and since the position of the cuts can be selected at will, the actual volume of each briquette so cut from the block can be controlled very accurately.
The selection of the actual volume of each briquette is governed by a number of factors.
For some applications, the quality of the final foodstuff may be of paramount importance. In that event the volume of each briquette is selected so as to be just less than the volume of the cavity when the tooling is closed. Typically a volume equivalent to 95% of the cavity volume is chosen. However it is to be understood that this is merely illustrative of the undersize volume of product and undersize volumes in the range 90-99% can be considered.
It is to be understood that the smaller or greater the discrepancy between the volume of the briquette and the volume of the cavity when the tooling is closed, so the final shape of the formed briquette will more or less correspond precisely to the internal shape of the cavity. Thus with a 97% volume fill factor, a very good approximation to the desired final shape and configuration of the formed briquette will be achieved, whereas with a 91% or 92% volume fill factor, the external appearance of the formed briquette could be less than perfect.
If the appearance of the final product is of importance, then the volume of the briquette should equal the volume of the cavity.
However if the actual appearance of the final product is of paramount importance, and texture and bite is deemed of secondary importance, then it may be preferred to cut the briquettes from the block of frozen consolidated material so that they are very slightly over-size in terms of volume, relative to the actual volume of the cavity, and to accept the marginal crushing of the material when the tooling closes.
Typically over-size volume lies in the range 100% to 105% of the cavity volume.
In a 105% overfill situation this excess material will tend to be crushed during the final of the tooling, and it is this crushing which can alter the bite and texture of the final product when cooked and eaten.
In order to accommodate excess material, the tooling may include a displaceable section or an opening in for example an end region thereof which is left open so that material can flow into that space under the pressure exerted on the briquette during the forming process.
The invention thus provides a method of cutting a block of material into briquettes which when formed under pressure in a mould tool, will produce either damage-free product but possibly imperfectly shaped product at one end of the spectrum, damage-free and perfectly shaped product if 100% fill factor is employed and perfectly shaped but marginally inferior product as regards texture and bite if over-size briquettes are cut from the block.
The invention thus envisages accurate dimensioning of a block of frozen consolidated product and the accurate cutting from the block of briquettes of the frozen foodstuff, each having an identical volume which is determined by reference to the cavity volume of the forming tooling when the tooling parts are closed so as to ensure that the final product when released from the tooling is either damage free and perfectly formed, or damage free and possibly imperfectly formed, or perfectly formed and subject to marginal texture damage as a result of crushing forces within the forming process.
The process includes the step of determining the volume of the tooling when closed by for example pouring in a thermo-setting compound such as wax, and determining the volume of the latter which just fills the volume of the cavity.
Since the tooling may be left in place for producing large numbers of similar product pieces, it is in general only necessary to perform the volume measuring step once, and for this volume to then be stored for the tooling concerned.
When tooling is changed or a different part of multiple chamber tooling is used, it is only necessary to call up the stored volume for the appropriate tooling or tooling chamber, and use that in the computation of the cutting programme for a block of frozen foodstuff material which is to be cut up prior to being formed.
The cutting process may be automated by sensing the dimensions of the block of frozen foodstuff and entering the dimensions into a computer having stored therein the desired volume for each briquette to be cut from the block, and programme the computer to determine the position and nature of the different cuts to be made from the block to secure the desired briquette volumes.
Where a block cannot be cut up exactly, the computer is preferably programmed so as to leave appropriately cross-sectioned briquettes of inadequate length which can then be collected and aligned end to end to form a continuous length of material which can then be guillotined into correct length briquettes for feeding into the tooling.
The invention will now be described by way of example, with reference to the accompanying drawings, in which: